1. Field of the Invention
The present invention relates to a surface grinding apparatus. More particularly, the present invention relates to a surface grinding apparatus for uniformly and efficiently grinding surfaces of various materials having a flat surface and differing in shape, such as plate-like and disk-like materials composed of metals, glass, synthetic resins, or the like.
2. Description of the Related Art
The surface grinding of metal plates, glass sheets, synthetic resin plates and the like is often performed by a lapping machine. Such a machine is provided with a plate-like lapping platen or a lapping platen having an artificial suede leather bonded thereto, and a material to be ground is pressed against the lapping platen, a grinding slurry containing abrasive grains is continuously supplied, and the material is slidingly moved on the lapping platen. Various lapping machines are known for performing such grinding operations, for example, a lapping machine in which a single lapping platen is rotated to effect grinding, and a lapping machine in which a material to be ground is gripped between upper and lower lapping platens rotated in opposite directions, to simultaneously grind both surfaces of the material.
In each of these known machines, grinding is carried out while continuously supplying a slurry containing a high concentration of abrasive grains onto the surface of the material to be ground. These abrasive grains, however, contaminate the apparatus and equipment, and further, the amount of abrasive grains effectively involved in the grinding is very small, although a large quantity of abrasive grains is used overall, which increases the grinding cost. Also, the waste liquid containing the abrasive grains and grinding residue must be treated before discharge.
To overcome these defects, it has been proposed to mount a solid grinding wheel having abrasive grains incorporated therein on a lapping platen, and perform grinding with a steady supply of water or water containing a small amount of a surface active agent instead of the abrasive grain-containing slurry. This method, however, is defective in that abrasive grains detached from the grinding wheel, and the grinding residue, penetrate fine pores on the surface of the grinding wheel, causing overloading and necessitating frequent dressing operations to prevent a reduction of the grinding power.